ABSTRACT
The methyl, ethyl, propyl, butyl, and heptyl esters of p-hydroxybenzoic acid are allowed for direct addition to foods as antimicrobials in various countries. Esterification of the carboxyl group of benzoic acid allows the molecule to remain undissociated up to pH 8.5. Thus they are one of the few food antimicrobials that can be used in low-acid food products. The antimicrobial activity of parabens has been evaluated against a wide variety of Gram-negative and Gram-positive food-related bacteria. As the alkyl chain length of the parabens increases, inhibitory activity generally increases. The antifungal effectiveness of the parabens also has been evaluated against many food-related fungi. In comparison to bacteria, fungi are much more susceptible to parabens. As with bacteria, inhibition increases with alkyl chain length. While an exact cause and effect relation for the mode of action of parabens has not been established, various studies have shown that these compounds may be most active at the cytoplasmic membrane. Parabens are apparently not widely applied to foods despite their regulatory approval. This is possibly because of the some of the controversial toxicology concerns. However, no objective evidence has demonstrated any significant risk from current food usage of parabens.
